The present invention relates generally to novel cartridges for use in weapons of various types. More specifically, the present invention relates to a novel ammunition cartridge structure using a plastic casing, and a method for manufacturing the plastic casing.
Heretofore, ammunition casings have been manufactured primarily by using brass. However, the use of brass casings for ammunition has several significant drawbacks. First, the use of brass is costly, particularly when copper is in short supply, and that cost is passed along to the consumer. Secondly, the brass component of bullets adds significant weight to the bullet, which creates a significant burden to those who must carry large amounts of ammunition, particularly including hunters, members of the military, and law enforcement. Additionally, in order to prevent the deleterious effects that high humidity and other extreme environmental conditions may have on ammunition over time, costly protective measures must be adopted.
To overcome these disadvantages, other plastic bullet cases have been proposed, but each effort has resulted in its own set of problems. Some plastic casings have failed because the plastic component could not withstand the high temperatures associated with repeated, rapid firings, thus resulting in a melting or softening of the plastic during use. Other plastic ammunition casings are not strong enough to withstand the violent extraction action of the weapon, so that the casing fails structurally and fragment as it is being ejected from the weapon, which causes fragments of the casings then become lodged in the weapon. Further, many of the plastic casings that have been proposed include complicated designs requiring multiple, time consuming manufacturing steps. Thus, the plastic casings proposed to date have significant disadvantages, and have not been adopted on a mass commercial scale.
Therefore, it would be desirable to provide a method of producing a non-metallic, preferably plastic, ammunition casing that is simple and inexpensive to manufacture. Additionally, it would be desirable to provide a plastic ammunition casing using a polymeric material that has a high enough melting temperature to withstand the heat produced during the rigors of rapid automatic fire, and that is strong enough to be extracted from an automatic weapon without suffering structural failure. Such plastic bullet casings would provide a reduction in cost of training and combat ammunition, reduction in weight of ammunition with consequent logistic advantages, improved reliability, and reduced weapon jamming problems.